There is a destructive readout memory in which the recorded data is destroyed when the data is read. When data needs to be retained continuously in a destructive readout memory even after read therefrom, the data is written back to the destructive readout memory. For a destructive readout memory having a limited number of writes, each time data read from the destructive readout memory is written back thereto, the number of writes increases to shorten the life of the destructive readout memory.